Fastening machines, i.e., machines that insert fastener parts during the assembly of a structure, are used in a variety of industrial environments. In the aircraft industry, fastening machines that automatically drill a hole and install a fastener, e.g., a rivet, are used in the fabrication of wings and other parts of an aircraft. Fastening machines designed for the aircraft industry are usually capable of installing a variety of both headed and nonheaded fasteners. In some cases different fasteners are intermixed during the course of assembly. Accordingly, fastening machines must be fed with fasteners delivered in a particular order of types and sizes. To this end, a modern fastener selection apparatus must be capable of automatically selecting the required fastener from a supply of fasteners. Since the most economical way of storing fasteners is in a plurality of contained, randomly-oriented piles, a fastener selection apparatus must be capable of selecting the appropriate pile and segregating a single fastener from the selected pile before directing it into the feeder system of the fastening machine.
One presently available apparatus for segregating a fastener from a pile for delivery to a fastening machine is a plural vibratory bowl apparatus, i.e., an apparatus that includes a plurality of bowls, each filled with fasteners of a given size and type. The bowls are vibrated in a manner that causes the fasteners in the bottom of the bowl to creep up a spiral track fixed along the inside of the bowl. The fasteners exit the vibrating bowls one at a time and are directed through a chute or channel into the feeder system of the fastening machine. Since each bowl can handle only a single size and type of fastener, this apparatus has the disadvantage of requiring a substantial amount of space to accommodate the many bowls required for the many sizes of fasteners used in a modern assembly plant. While hand fastener selection can be used, this method has the disadvantage of being slow and subject to the errors encountered when humans are employed for tedious, repetitive tasks. Hence, there is a need for fastener selection apparatus that is relatively small and reliable.